Determine the drain current (PMOS-transistor)

circuit analysistransistors

I have the following problem:

Consider the circuit below

enter image description here

These component values are given: \$R_{G2}=1.5\text{M}\Omega\$, \$R_{G1}=1.2\text{M}\Omega\$, \$K=2.3\frac{\text{mA}}{\text{V}^2}\$,\$V_{to}=-1.8\text{V}\$, \$V_{cc}=5\text{V}\$.

What is the drain current, \$i_D\$?

Okay, so my thought of solving this would be the following.

First find the voltage-drop across \$R_{G2}\$ through voltage division.

\$V_{G1}=V_{cc}\times \frac{R_{G2}}{R_{G1}+R_{G2}}=5\text{V}\times\frac{1.5\text{M}\Omega}{2.7\text{M}\Omega} =2.78\text{V}\$

I interpret this as also being the voltage at the gate of the pmos. That results in \$V_{GS}=2.78-5=-2.22\text{V}\$

And I'm stuck here. My next step would be to find \$V_{DS}\$, but I am unsure of how to do so. Can anyone help me?

Best Answer

$$\ I_{D} = \frac{\textrm{Kp}}{2}(V_{GS}-V_T)^2 $$ $$\ I_D =\frac{\textrm{2.3}}{2}((-2.22V)-(1.8V))^2 = 0.203 \textrm{m} A = 203 \mu A $$

Found this : https://vlsitips.blogspot.com/2012/06/vlsi-physical-design.html Operation Modes for PMOS